SIMULTANEOUS DETERMINATION OF CHLOROQUINE AND ITS DESETHYL METABOLITE IN HUMAN-PLASMA BY GAS-CHROMATOGRAPHY

A gas chromatographic method for the simultaneous determination of chloroquine and its metabolite desethylchloroquine in plasma is described. Chloroquine, desethylchloroquine and internal standard are extracted as bases with n-hexane-pentanol (90:10) and then back-extracted to an acid aqueous phase. The aqueous phase is made alkaline and after re-extraction into chloroform and evaporation of the chloroform, acylation with trifluoroacetic anhydride is performed. Separation is achieved on an OV-17 column at 250.degree. C. Chloroquine and desethylchloroquine can be determined down to 0.1-0.2 .mu.mol/l (30-60 ng/ml), with a coefficient of variation of 12%, using a N detector. The method shows good correlation (r = 0.98) with a recently developed liquid chromatographic method. Chloroquine is one of the most frequently used antimalarial agents and is used as an effective drug in the treatment of rheumatoid arthritis.